Detergent compositions



United States Patent Ofiice No Drawing. Filed Mar. 1, 1960, Ser. No. 12,004 '7 Claims. (Cl. 252-121) This invention relates to compositions containing sodium cellulose acetate sulfate as a new and improved type of detergent additive for the prevention of soil redeposition during the laundering of textile fabrics. This invention particularly relates to compositions of sodium cellulose acetate sulfate with detergents and to the process of removing dirt from washable materials therewith.

In the Washing of fabrics with detergents the process can be considered as a two-step operation. In the first stage the detergent removes the soil particles from the cloth and suspends them in the solution. In the second stage the detergent prevents the soil particles from redepositing on the cloth before the fabric is removed from the dirty soil solution or during the rinsing cycles. It is thought that this second stage is accomplished by the formation of a charge on the surface of the fabric being washed, this charge repelling the soil particles which carry a similar charge. Regardless of the mode of operation, the effect is that soil particles are suspended in the solution in such a manner that they do not redeposit on the cloth.

In general, aqueous washing media containing soap fulfill both of these criteria .as soap is not only a good soil remover but also keeps the removed soil in suspension so that little redeposition takes place. However, the present trend is toward the use of synthetic detergents, since, unlike soap, they are not precipitated by the calcium, magnesium and other divalent salt metal ions present in hard water. Examples of satisfatcory synthetic detergents are the various alkyl and aryl sulfonates and sulfates, which are termed anionic detergents and the various nonionic detergents examples of which are polyethylene glycol esters of stearic acid and alkyl phenyl polyethylene glycol ethers. The synthetic detergents are very good soil removers but usually are not very effective in preventing soil redeposition on cotton fabric during laundering.

Several water soluble polymers such as carboxymethyl celluose, polyvinyl alcohol, polyvinyl pyrrolidone and cellulose and starch esters of sulfuric acid have been claimed to be good detergent additives. By detergent additive is meant an additive which when added to a detergent in low concentrations, such as 110% based on the weight of the detergent, prevents soil redeposition on cotton fabrics during laundering. My Canadian Patent No. 545,126 describes the use of sulfuric acid esters of cellulose and starch for this purpose.

One object of my invention is to disclose a new and improved detergent additive which prevents soil redeposition on cotton fabrics during laundering. Another object of my invention is to disclose a detergent additive which also functions as a foaming agent. A further object of my invention is to disclose a detergent additive which aids the detergent in lowering the surface tension of Water. A still further object of my invention is to disclose a more effective cellulose sulfate type of detergent additive than the simple sulfuric acid esters of cellulose disclosed in my Canadian Patent 545,126.

Patented Feb. 22, 1966 I have found that water soluble salts of cellulose acetate sulfate containing an average of 12.2 acetyl groups and 0.4-1.0 sulfate group per anhydroglucose unit are better detergent additives than the simple sulfuric acid esters of cellulose. Water solutions of sodium cellulose acetate sulfate have excellent foaming properties whereas solutions of sodium cellulose sulfate are not characterized by very much foaming in use. The art recognizes that a certain amount of foam is desirable in a detergent solution in washing textile fabrics. Also sodium cellulose acetate sulfate functions to some extent as a detergent as Well as a detergent additive, probably due to the lower surface tension of water solutions of sodium cellulose acetate sulfate.

In general my invention involves the mixing of sodium cellulose acetate sulfate and a detergent which is adapted to be used in an aqueous system, the former comprising approximately 110% of the composition. The water soluble salts of cellulose acetate sulfate which are useful in carrying out this invention are the alkali-metal salts or the ammonium or amine salts of those cellulose derivatives. The cellulose acetate sulfate derivatives are conveniently prepared by reacting cellulose with an esterifying solution containing acetic acid, acetic anhydride and sulfuric acid or sodium acid sulfate as described in US. Patents No. 2,582,009 and 2,622,079. The cellulose acetate sulfate salts may be mixed with any of the commonly known anionic or nonionic detergents such as soap, alcohol sulfates, alkyl aryl sulfonates, alkyl sulfonates, sulfated or sulfonated amides, esters and amines, nonionic substances, or for example, polyglycol ether or any of the miscellaneous types not readily classified. The detergent should be one employed in an aqueous system. The detergent may contain an inorganic salt commonly referred to as a builder such as sodium sulfate, sodium silicate, sodium phosphate or the like. The ratio of detergent to additive by weight may vary over a Wide range depending to some extent on the type of detergent used and the amount of soil which is to be removed from the fabric. Usually approximately ll0% of detergent additive based on the combined weight of detergent and builder is suflicient. The preferred range is l-5%.

The following examples illustrate my invention:

Example 1 A series of washings were carried out in which the detergent solutions used consisted of 0.15% detergent, 0.05% sodium tripolyphosphate (builder) and 99.8% water. Where detergent additive was used, 0.01 g. thereof was dissolved in ml. of the detergent solution and 5 cc. of a carbon soil suspension (0.025 g. of carbon suspended in water) was added. The soil suspension used was prepared from a 35% aqueous suspension of carbon black manufactured by Binney and Smith Company under the trade name Aqua Black-B. The mixture was preheated to F. for 10 minutes whereupon a 2 x 2 /z-inch piece of unsized white cotton cloth was added. The various solutions were placed in a standard Launder-O-Meter and the machine was operated at a temperature of 140 F. for 30 minutes. Reflectance measurements were made on the rinsed and dried cloth swatches. The results obtained using several built detergent formulations containing sodium cellulose acetate sulfate, a low sulfur sodium cellulose sulfate (6% S), and a higher sulfur (19%) sodium cellulose sulfate are shown in the following table. The

low sulfur content sodium cellulose sulfate was prepared according to Example 2 of US. Patent No. 2,559,914 of Frank. The high sulfur content sodium cellulose sulfate was prepared in accordance with the method described in British Patent No. 485,649, chlorosulfonic acid dissolved in pyridine having been used in preparing the product. The sodium cellulose acetate sulfates employed were prepared acording to the method described in US. Patent No. 2,622,079 of Crane. The values given illustrate that sodium cellulose acetate sulfate is more effective as a detergent additive than either high or low sulfur content sodium cellulose sulfate.

Percent Reflectance for Four (Millimicron) SwIz Itch Detergent Additive Wavelengths 1 Igepon T None s. 31 33 35 37 2 d S.C.S. (6 S) G4 65 07 71 8.0.8. (19% S) 52 56 57 59 S.C.A.S. (7% S) (27% 71 75 76 79 acetyl S.C.A.S. (9% S) (20% G8 72 74 79 acetyl). None 29 31 35 37 S.C.S. (6% 60 59 65 8.05. (19% S) 58 59 64 67 S.C.A.S. (7% S) (27% 65 65 70 69 ncet S.C.A.S. (9% S) 61 G4 68 69 acetyl). None 29 32 33 36 acetyl). S.C.A.S. (9% S) (20% 59 58 G0 61 acetyl). 16 Pluronic None 27 29 3O 33 8.0.8. (6% S) 65 67 68 68 8.0.8. (19% S) G0 61 61 64 S.C.A.S. (7% S) (27% 73 74 76 79 aeety S.C.A.S. (9% S) (20% 7O 70 71 72 acetyl).

1 Sodium N-methyl-N-oleoyl taurate (General Aniline and Film Corporation).

Sodium sulfate derivative of 7-ethyl-2-methyl, 4-undecanol (Union Carbide Chemicals Company).

3 Alkyl aryl sodium sulfonate (Wyandotte Chemicals Corporation).

4 A condensate of ethylene oxide with a hydrophobic base formed by condensing propylene oxide with propylene glycol (Wyandotte Chemicals Corporation).

Example 2 2% solution of sodium cellulose sulfate and sodium cellulose acetate sulfate were prepared and the surface tension of the solutions was tested. The results show the superior surface tension properties of the sodium cellulose acetate sulfate. The results obtained were as follows:

Surface tension Sample: (dynes/cm.)

Water 72.4 2% water solution of sodium cellulose sulfate (6% S) 70.8 2% water solution of sodium cellulose sulfate (19% S) 69.3 2% water solution of sodium cellulose acetate sulfate (7% S and 27% acetyl) 60.3 2% water solution of sodium cellulose acetate sulfate (9% S and 20% acetyl) 61.5

Example 3 Sodium cellulose acetate sulfate has foaming characteristics superior to the sodium cellulose sulfates as shown by the preparation of aqueous solutions of sodium cellulose sulfate and sodium cellulose acetate sulfate of 1% concentration. The solutions, after shaking vigorously for 5 minutes, were allowed to stand. After 3 minutes substantially all of the foam had disappeared from a solution of sodium cellulose sulfate. A sodium cellulose acetate sulfate solution, on the other hand, still contained 1-2 inches of foam even after standing for 10 minutes.

I claim:

1. A composition soluble in water to form a washing solution which is effective not only to remove soil from textile materials but also to minimize re-deposition of removed soil comprising the mixture of a detergent selected from the group consisting of water-soluble soap, the water soluble synthetic nonionic organic detergents and the water-soluble synthetic organic anionic sulfated and sulfonated detergents with 110% by weight based on the dry weight of the detergent of a water-soluble salt selected from the group consisting of the alkali metal, ammonium and amine salts of the cellulose acetate sulfates having 1-2.2 acetyl groups and 0.41 sulfate radicals per anhydroglucose unit of cellulose.

2. The composition of claim 1 wherein the detergent is a water soluble synthetic organic anionic sulfated detergent.

3. The composition of claim 1 wherein the detergent is a water soluble synthetic organic nonionic detergent.

4. The composition of claim 1 wherein the water soluble detergent is sodium N-methyl-N-oleoyl taurate and the cellulose acetate sulfate salt is sodium cellulose acetate sulfate.

5. The composition of claim 1 wherein the detergent is the sodium sulfate derivative of 7-ethyl-2-methyl, 4-undecanol.

6. A composition soluble in water to form .a washing solution which is effective not only to remove soil from textile materials but also to minimize re-deposition of removed soil essentially consisting of an alkyl aryl sodium sulfonate and 110% by weight, based on the dry weight of the alkyl aryl sodium sulfonate, of cellulose acetate sodium sulfate having 12.2 acyl groups and 0.41 sulfate radicals per anhydroglucose unit of cellulose.

7. A method of cleaning fabrics which comprises agitating them in a dilute solution in water of a composition comprising a detergent selected from the group consisting of water soluble soap, the water soluble synthetic nonionie organic detergents and the water soluble synthetic anionic sulfated and sulfonated detergents and 110% by weight, based on the dry weight of the detergent, of cellulose acetate sodium sulfate having l-2.2 acetyl groups and 0.4-1 sulfate radicals per anhydroglucose unit of cellulose.

References Cited by the Examiner UNITED STATES PATENTS 1,866,532 7/1932 Haskins 260-215 2,582,009 1/1952 Crane 260-215 2,622,079 12/ 1952 Crane 260-2l5 FOREIGN PATENTS 545,126 8/1957 Canada. 729,531 5/1955 Great Britain.

OTHER REFERENCES Surface Active Agents, Interscience Publishers (Schwartz et al.), pages 234-6, 378-80 1949 JULUIS GREENWALD, Primary Examiner.

JOSEPH R. LIBERMAN, Examiner. 

1. A COMPOSITION SOLUBLE IN WATER TO FORM A WASHING SOLUTION WHICH IS EFFECTIVE NOT ONLY TO REMOVE SOIL FROM TEXTILE MATERIALS BUT ALSO TO MINIMIZE RE-DEPOSITION OF REMOVED SOIL COMPRISING THE MIXTURE OF S DETERGENT SELECTED FROM THE GROUP CONSISTING OF WATER-SOLUBLE SOAP, THE WATER SOLUBLE SYNTHETIC NONIONIC ORGANIC DETERGENTS AND THE WATER-SOLUBLE SYNTHETIC ORGANIC ANIONIC SULFATED AND SULFONATED DETERGENTS WITH 1-10% BY WEIGHT BASED ON THE DRY WEIGHT OF THE DETERGENT OF A WATER-SOLUBLE SALT SELECTED FROM THE GROUP CONSISTING OF THE ALKALI METAL, AMMONIUM AND AMINE SALTS OF THE CELLULOSE ACETATE SULATES HAVING 1-2.2 ACETYL GROUPS AND O.4-1 SULFATE RADICALS PER ANHYDROGLUCOSE UNIT OF CELLULOSE. 